Wide-angle lens

ABSTRACT

Provided is a wide-angle lens, including a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, and a seventh lens, sequentially arranged from an object side. An object-to-image distance of the wide-angle lens is set to d, an entrance pupil diameter of the wide-angle lens is set to HEP, and d/HEP&lt;29.000 is satisfied.

CROSS REFERENCE TO RELATED APPLICATIONS

The present invention claims priority under 35 U.S.C. § 119 to ChineseApplication No. 201911281254.4 filed on Dec. 13, 2019, the entirecontent of which is incorporated herein by reference.

FIELD OF THE INVENTION

The disclosure relates to a wide-angle lens.

BACKGROUND

As a wide-angle lens for an in-vehicle camera, there has conventionallybeen a wide-angle lens including, sequentially arranged from an objectside, a first lens, a second lens, a third lens, a fourth lens, adiaphragm, a fifth lens, a sixth lens and a seventh lens.

In practice, sometimes the space for mounting the wide-angle lens in avehicle may have a limited length in the optical axis direction of thewide-angle lens. Therefore, it has been desired to ensure the opticalperformance of the wide-angle lens while preventing the overall lengthof the wide-angle lens from becoming excessively large.

SUMMARY

An exemplary embodiment of the disclosure provides a wide-angle lens,including a first lens, a second lens, a third lens, a fourth lens, adiaphragm, a fifth lens, a sixth lens, and a seventh lens, sequentiallyarranged from an object side. An object-to-image distance of thewide-angle lens is set to d, an entrance pupil diameter of thewide-angle lens is set to HEP, and d/HEP<29.000 is satisfied.

The above and other elements, features, steps, characteristics andadvantages of the present disclosure will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wide-angle lens according to Embodiment 1 of thedisclosure.

FIG. 2A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 1 of the disclosure.

FIG. 2B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 1 of the disclosure.

FIG. 3A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 1 of thedisclosure.

FIG. 3B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 1 of the disclosure.

FIG. 4A to FIG. 4L illustrate transverse aberration of the wide-anglelens according to Embodiment 1 of the disclosure.

FIG. 5 illustrates a wide-angle lens according to Embodiment 2 of thedisclosure.

FIG. 6A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 2 of the disclosure.

FIG. 6B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 2 of the disclosure.

FIG. 7A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 2 of thedisclosure.

FIG. 7B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 2 of the disclosure.

FIG. 8A to FIG. 8L illustrate transverse aberration of the wide-anglelens according to Embodiment 2 of the disclosure.

FIG. 9 illustrates a wide-angle lens according to Embodiment 3 of thedisclosure.

FIG. 10A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 3 of the disclosure.

FIG. 10B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 3 of the disclosure.

FIG. 11A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 3 of thedisclosure.

FIG. 11B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 3 of the disclosure.

FIG. 12A to FIG. 12L illustrate transverse aberration of the wide-anglelens according to Embodiment 3 of the disclosure.

FIG. 13 illustrates a wide-angle lens according to Embodiment 4 of thedisclosure.

FIG. 14A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 4 of the disclosure.

FIG. 14B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 4 of the disclosure.

FIG. 15A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 4 of thedisclosure.

FIG. 15B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 4 of the disclosure.

FIG. 16A to FIG. 16L illustrate transverse aberration of the wide-anglelens according to Embodiment 4 of the disclosure.

FIG. 17 illustrates a wide-angle lens according to Embodiment 5 of thedisclosure.

FIG. 18A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 5 of the disclosure.

FIG. 18B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 5 of the disclosure.

FIG. 19A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 5 of thedisclosure.

FIG. 19B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 5 of the disclosure.

FIG. 20A to FIG. 20L illustrate transverse aberration of the wide-anglelens according to Embodiment 5 of the disclosure.

FIG. 21 illustrates a wide-angle lens according to Embodiment 6 of thedisclosure.

FIG. 22A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 6 of the disclosure.

FIG. 22B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 6 of the disclosure.

FIG. 23A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 6 of thedisclosure.

FIG. 23B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 6 of the disclosure.

FIG. 24A to FIG. 24L illustrate transverse aberration of the wide-anglelens according to Embodiment 6 of the disclosure.

FIG. 25 illustrates a wide-angle lens according to Embodiment 7 of thedisclosure.

FIG. 26A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 7 of the disclosure.

FIG. 26B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 7 of the disclosure.

FIG. 27A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 7 of thedisclosure.

FIG. 27B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 7 of the disclosure.

FIG. 28A to FIG. 28L illustrate transverse aberration of the wide-anglelens according to Embodiment 7 of the disclosure.

FIG. 29 illustrates a wide-angle lens according to Embodiment 8 of thedisclosure.

FIG. 30A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 8 of the disclosure.

FIG. 30B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 8 of the disclosure.

FIG. 31A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 8 of thedisclosure.

FIG. 31B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 8 of the disclosure.

FIG. 32A to FIG. 32L illustrate transverse aberration of the wide-anglelens according to Embodiment 8 of the disclosure.

FIG. 33 illustrates a wide-angle lens according to Embodiment 9 of thedisclosure.

FIG. 34A illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 9 of the disclosure.

FIG. 34B illustrates curvature of field and distortion of the wide-anglelens according to Embodiment 9 of the disclosure.

FIG. 35A illustrates lateral chromatic aberration (transverse chromaticaberration) of the wide-angle lens according to Embodiment 9 of thedisclosure.

FIG. 35B illustrates spherical aberration (longitudinal aberration) ofthe wide-angle lens according to Embodiment 9 of the disclosure.

FIG. 36A to FIG. 36L illustrate transverse aberration of the wide-anglelens according to Embodiment 9 of the disclosure.

DETAILED DESCRIPTION

Hereinafter, each embodiment of a wide-angle lens of the disclosure willbe described with reference to the accompanying drawings. In thefollowing description, in an extension direction of an optical axis L,an object side is denoted by L1, and an image side is denoted by L2.

FIG. 1 illustrates a wide-angle lens according to Embodiment 1 of thedisclosure. FIG. 2A illustrates curvature of field and distortion of thewide-angle lens according to Embodiment 1 of the disclosure. FIG. 2Billustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 1 of the disclosure. FIG. 3A illustrates lateralchromatic aberration (transverse chromatic aberration) of the wide-anglelens according to Embodiment 1 of the disclosure. FIG. 3B illustratesspherical aberration (longitudinal aberration) of the wide-angle lensaccording to Embodiment 1 of the disclosure. FIG. 4A to FIG. 4Lillustrate transverse aberration of the wide-angle lens according toEmbodiment 1 of the disclosure. Here, in FIG. 2A, FIG. 2B, FIG. 3A, FIG.3B, and FIG. 4A to FIG. 4L, a correlation curve of red light R (having awavelength of 656 nm) is denoted by R, a correlation curve of greenlight G (having a wavelength of 588 nm) is denoted by G, and acorrelation curve of blue light B (having a wavelength of 486 nm) isdenoted by B. T indicates being related to the meridian plane, and Sindicates being related to the sagittal plane. Moreover, in FIG. 4A toFIG. 4L, a maximum scale of the longitudinal axis is ±50.000 μm.

As shown in FIG. 1, a wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), a first lens 110, a second lens120, a third lens 130, a fourth lens 140, a diaphragm 180, a fifth lens150, a sixth lens 160 and a seventh lens 170. Among them, the sixth lens160 and the seventh lens 170 are bonded together by an adhesive toconstitute a cemented lens.

Here, the first lens 110 is a lens (simply referred to as negative lens)with negative refractive power, having a convex surface (first surface1) facing the object side L1 and a concave surface (second surface 2)facing the image side L2. In this embodiment, the first lens 110 is aglass lens in which the first surface 1 and the second surface 2 arespherical surfaces.

The second lens 120 is a lens with negative refractive power, having aconvex surface (third surface 3) facing the object side L1 and a concavesurface (fourth surface 4) facing the image side L2. In this embodiment,the second lens 120 is a plastic lens in which the third surface 3 andthe fourth surface 4 are aspherical surfaces.

The third lens 130 is a lens (simply referred to as positive lens) withpositive refractive power, having a concave surface (fifth surface 5)facing the object side L1 and a convex surface (sixth surface 6) facingthe image side L2. In this embodiment, the third lens 130 is a plasticlens in which the fifth surface 5 and the sixth surface 6 are asphericalsurfaces.

The fourth lens 140 is a lens with positive refractive power, having aconcave surface (seventh surface 7) facing the object side L1 and aconvex surface (eighth surface 8) facing the image side L2. In thisembodiment, the fourth lens 140 is a plastic lens in which the seventhsurface 7 and the eighth surface 8 are aspherical surfaces.

The fifth lens 150 is a lens with positive refractive power, having aconvex surface (tenth surface 10) facing the object side L1 and a convexsurface (eleventh surface 11) facing the image side L2. In thisembodiment, the fifth lens 150 is composed of a glass lens.

The sixth lens 160 is a lens with negative refractive power, having aconcave surface (twelfth surface 12) facing the object side L1 and aconcave surface (thirteenth surface 13) facing the image side L2. Thesixth lens 160 constitutes a cemented lens with the seventh lens 170. Inthis embodiment, the sixth lens 160 is a plastic lens in which thetwelfth surface 12 and the thirteenth surface 13 are asphericalsurfaces.

The seventh lens 170 is a lens with positive refractive power, having aconvex surface (thirteenth surface 13) facing the object side L1 and aconvex surface (fourteenth surface 14) facing the image side L2. In thisembodiment, the seventh lens 170 is a plastic lens in which thethirteenth surface 13 and the fourteenth surface 14 are asphericalsurfaces.

In addition, in this embodiment, as shown in FIG. 1, a light-shieldingsheet 190 is provided between the second lens 120 and the third lens130, a filter 200 is arranged on the image side of the seventh lens 170,and an imaging element 300 is arranged on the image side of the filter200.

In this embodiment, in the lens system as a whole, an effective focallength f is 1.023 mm, an object-to-image distance (total track) d is13.611 mm, an F value (image space F/#) is 2.02, a maximum half field ofview (HFOV) (maximum half field angle) is 115 degrees, and an entrancepupil diameter HEP is 0.507 mm.

Table 1 shows physical properties of each surface of the wide-angle lens1000 of this embodiment. Table 2-1 and Table 2-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 1 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  11.4201.510 1.871 40.73 −5.963 −1.338 3.148 2  3.350 2.050 3* 40.687 0.6001.544 56.4 −2.328 4* 1.222 1.427 5* −11.789 0.689 1.544 56.4 6.742 3.1226* −2.855 0.597 7* −13.315 0.778 1.635 23.9 4.923 8* −2.589 −0.039 9 Infinite 0.257 (diaphragm) 10  15.150 1.288 1.697 55.46 3.175 3.740 11 −2.501 0.101 12*  −5.143 0.500 1.635 23.9 −1.297 13.449 13*  1.018 2.3621.544 56.4 1.745 14*  −2.561 0.965 15  Infinite 0.400 16  Infinite 0.125

In Table 1 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 2-1 Surface c (1/radius of curvature) K A4 A6 3  2.45778E−020.00000E+00 −7.34647E−04  0.00000E+00 4  8.18649E−01 −1.00000E+00 3.34909E−02 1.52429E−02 5 −8.48284E−02 0.00000E+00 −1.05901E−02 2.28744E−02 6 −3.50286E−01 0.00000E+00 4.60516E−02 1.35719E−02 7−7.51052E−02 0.00000E+00 6.96916E−02 5.26973E−04 8 −3.86206E−010.00000E+00 4.85130E−02 1.07658E−02 12 −1.94439E−01 0.00000E+001.37213E−02 −3.80723E−02  13  9.82404E−01 −1.00000E+00  2.47704E−01−2.97167E−01  14 −3.90445E−01 0.00000E+00 2.43790E−02 −1.73998E−02 

TABLE 2-2 Surface A8 A10 A12 A14 A16 3 0.00000E+00 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 4 −3.29328E−03  2.82298E−03−4.88754E−04  0.00000E+00 0.00000E+00 5 −5.12306E−03  0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 6 0.00000E+00 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 7 4.37857E−03 2.92148E−030.00000E+00 0.00000E+00 0.00000E+00 8 −5.94177E−03  1.11565E−020.00000E+00 0.00000E+00 0.00000E+00 12 1.79956E−02 −7.87537E−04 −1.30556E−03  0.00000E+00 0.00000E+00 13 1.73181E−01 −4.77496E−02 4.65741E−03 0.00000E+00 0.00000E+00 14 1.34046E−02 −4.35536E−03 5.73510E−04 0.00000E+00 0.00000E+00

In Table 2-1 and Table 2-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 2-1 and Table 2-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy the following expression (Expression 1). In thefollowing expression, Z represents sag (axis in an optical axisdirection), r represents height (ray height) in a directionperpendicular to the optical axis, K represents the conic coefficient,and c represents the reciprocal of the radius of curvature.

$\begin{matrix}{Z = {\frac{cr^{2}}{1 + \sqrt{1 - {\left( {1 + K} \right)c^{2}r^{2}}}} + {\sum\limits_{n = 2}^{5}{A_{2n}r^{2n}}}}} & \left\lbrack {{Expression}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Here, in the wide-angle lens 1000, the object-to-image distance d is13.611 mm, and the entrance pupil diameter HEP is 0.507 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.611 mm, and the effective focal length f of the lens system as awhole is 1.023 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.023 mm, and the entrance pupildiameter HEP is 0.507 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 3.148 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.740 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.740 mm, and the effective focal length f of the lenssystem as a whole is 1.023 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 2A to FIG. 4L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 5 illustrates a wide-angle lens according to Embodiment 2 of thedisclosure. FIG. 6A illustrates curvature of field and distortion of thewide-angle lens according to Embodiment 2 of the disclosure. FIG. 6Billustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 2 of the disclosure. FIG. 7A illustrates lateralchromatic aberration (transverse chromatic aberration) of the wide-anglelens according to Embodiment 2 of the disclosure. FIG. 7B illustratesspherical aberration (longitudinal aberration) of the wide-angle lensaccording to Embodiment 2 of the disclosure. FIG. 8A to FIG. 8Lillustrate transverse aberration of the wide-angle lens according toEmbodiment 2 of the disclosure. Here, in FIG. 6A, FIG. 6B, FIG. 7A, FIG.7B, and FIG. 8A to FIG. 8L, a correlation curve of red light R (having awavelength of 656 nm) is denoted by R, a correlation curve of greenlight G (having a wavelength of 588 nm) is denoted by G, and acorrelation curve of blue light B (having a wavelength of 486 nm) isdenoted by B. T indicates being related to the meridian plane, and Sindicates being related to the sagittal plane. Moreover, in FIG. 8A toFIG. 8L, the maximum scale of the longitudinal axis is ±50.000 μm.

As shown in FIG. 5, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 5, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.062 mm, the object-to-image distance (total track) d is13.610 mm, the F value (image space F/#) is 2.02, the maximum HFOV(maximum half field angle) is 115 degrees, and the entrance pupildiameter HEP is 0.526 mm.

Table 3 shows physical properties of each surface of the wide-angle lens1000 of this embodiment. Table 4-1 and Table 4-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 3 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  11.3631.561 1.871 40.73 −5.895 −1.406 4.237 2  3.310 2.024 3* 45.562 0.6001.544 56.4 −2.489 4* 1.309 1.360 5* −9.695 0.703 1.544 56.4 6.297 3.3806* −2.596 0.565 7* −4.818 0.732 1.635 23.9 5.955 8* −2.244 −0.043 9 Infinite 0.201 (diaphragm) 10  16.738 1.245 1.697 55.46 3.436 3.640 11 −2.709 0.244 12*  −6.978 0.500 1.635 23.9 −1.379 8.893 13*  1.029 2.4261.544 56.4 1.765 14*  −2.427 0.968 15  Infinite 0.400 16  Infinite 0.125

In Table 3 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 4-1 Surface c (1/radius of curvature) K A4 A6 3  2.19479E−020.00000E+00 −5.53459E−04   0.00000E+00 4  7.64121E−01 −1.00000E+00 4.76939E−02  1.87020E−03 5 −1.03144E−01 0.00000E+00 −4.63672E−04  2.39479E−02 6 −3.85243E−01 0.00000E+00 6.19526E−02  9.41258E−03 7−2.07563E−01 0.00000E+00 8.01905E−02 −1.81445E−02 8 −4.45687E−010.00000E+00 5.32792E−02 −3.21513E−03 12 −1.43308E−01 0.00000E+002.59200E−02 −4.54679E−02 13  9.71678E−01 −1.00000E+00  2.67381E−01−3.18917E−01 14 −4.11994E−01 0.00000E+00 2.93182E−02 −2.05884E−02

TABLE 4-2 Surface A8 A10 A12 A14 A16 3 0.00000E+00  0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 4 1.18832E−02 −3.21383E−037.23623E-04 0.00000E+00 0.00000E+00 5 −7.11892E−03   0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 6 0.00000E+00  0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 7 1.48329E−02 −9.20347E−040.00000E+00 0.00000E+00 0.00000E+00 8 3.16264E−03  4.17741E−030.00000E+00 0.00000E+00 0.00000E+00 12 −7.44565E−04  −1.42901E−030.00000E+00 0.00000E+00 0.00000E+00 13 1.80337E−01 −4.80759E−024.57265E−03 0.00000E+00 0.00000E+00 14 1.50208E−02 −4.69107E−035.90742E−04 0.00000E+00 0.00000E+00

In Table 4-1 and Table 4-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 4-1 and Table 4-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.610 mm, and the entrance pupil diameter HEP is 0.526 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.610 mm, and the effective focal length f of the lens system as awhole is 1.062 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.062 mm, and the entrance pupildiameter HEP is 0.526 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 4.237 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.640 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.640 mm, and the effective focal length f of the lenssystem as a whole is 1.062 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 6A to FIG. 8L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 9 illustrates a wide-angle lens according to Embodiment 3 of thedisclosure. FIG. 10A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 3 of the disclosure. FIG.10B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 3 of the disclosure. FIG. 11A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 3 of the disclosure. FIG. 11Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 3 of the disclosure. FIG. 12A toFIG. 12L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 3 of the disclosure. Here, in FIG. 10A, FIG.10B, FIG. 11A, FIG. 11B, and FIG. 12A to FIG. 12L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 12A to FIG. 12L, the maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 9, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 9, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.026 mm, the object-to-image distance (total track) d is13.403 mm, the F value (image space F/#) is 2.02, the maximum HFOV(maximum half field angle) is 109 degrees, and the entrance pupildiameter HEP is 0.508 mm.

Table 5 shows physical properties of each surface of the wide-angle lens1000 of this embodiment. Table 6-1 and Table 6-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 5 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  11.1711.300 1.871 40.73 −5.584 −1.467 3.572 2  3.204 1.815 3* 35.057 0.6001.544 56.4 −2.673 4* 1.388 1.422 5* −5.882 0.763 1.544 56.4 7.039 3.4566* −2.425 0.839 7* −6.368 0.718 1.635 23.9 5.655 8* −2.397 −0.037 9 Infinite 0.347 (diaphragm) 10  7.103 1.300 1.697 55.46 3.076 3.663 11 −2.839 0.135 12*  −4.077 0.500 1.635 23.9 −1.284 11.542 13*  1.068 2.2131.544 56.4 1.744 14*  −2.294 0.963 15  Infinite 0.400 16  Infinite 0.125

In Table 5 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 6-1 Surface c (1/radius of curvature) K A4 A6 3  2.85248E−020.00000E+00 −7.73953E−04  −2.76248E−05 4  7.20578E−01 −1.00000E+00 1.69157E−02  2.83585E−02 5 −1.69997E−01 0.00000E+00 4.77013E−03 1.28269E−02 6 −4.12314E−01 0.00000E+00 4.38590E−02  3.36563E−03 7−1.57044E−01 0.00000E+00 5.20793E−02 −9.74604E−03 8 −4.17218E−010.00000E+00 3.75209E−02 −1.18387E−03 12 −2.45256E−01 0.00000E+001.12258E−02 −2.18878E−02 13  9.36158E−01 −1.00000E+00  1.84892E−01−2.17248E−01 14 −4.35910E−01 0.00000E+00 6.08264E−02 −6.37284E−02

TABLE 6-2 Surface A8 A10 A12 A14 A16 3 0.00000E+00 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 4 −1.08170E−02  3.74135E−030.00000E+00 0.00000E+00 0.00000E+00 5 −6.95368E−04  2.73435E−050.00000E+00 0.00000E+00 0.00000E+00 6 2.29705E−03 −1.23857E−05 0.00000E+00 0.00000E+00 0.00000E+00 7 8.85677E−03 −7.73714E−05 0.00000E+00 0.00000E+00 0.00000E+00 8 4.43504E−03 9.66329E−040.00000E+00 0.00000E+00 0.00000E+00 12 3.37862E−04 9.82658E−03−3.53648E−03  −1.65685E−04  0.00000E+00 13 1.49413E−01 −7.49877E−02 2.96657E−02 −5.71297E−03  0.00000E+00 14 5.78846E−02 −2.66940E−02 6.28648E−03 −5.86821E−04  0.00000E+00

In Table 6-1 and Table 6-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 6-1 and Table 6-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.403 mm, and the entrance pupil diameter HEP is 0.508 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.403 mm, and the effective focal length f of the lens system as awhole is 1.026 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.026 mm, and the entrance pupildiameter HEP is 0.508 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 3.572 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.663 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.663 mm, and the effective focal length f of the lenssystem as a whole is 1.026 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 10A to FIG. 12L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 13 illustrates a wide-angle lens according to Embodiment 4 of thedisclosure. FIG. 14A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 4 of the disclosure. FIG.14B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 4 of the disclosure. FIG. 15A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 4 of the disclosure. FIG. 15Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 4 of the disclosure. FIG. 16A toFIG. 16L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 4 of the disclosure. Here, in FIG. 14A, FIG.14B, FIG. 15A, FIG. 15B, and FIG. 16A to FIG. 16L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 16A to FIG. 16L, the maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 13, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 13, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.011 mm, the object-to-image distance (total track) d is13.404 mm, the F value (image space F/#) is 2.03, the maximum HFOV(maximum half field angle) is 109 degrees, and the entrance pupildiameter HEP is 0.498 mm.

Table 7 shows physical properties of each surface of the wide-angle lens1000 of this embodiment. Table 8-1 and Table 8-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 7 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  11.8501.800 1.871 40.73 −4.888 −1.347 6.571 2  2.910 1.717 3* 23.043 0.6001.544 56.4 −2.540 4* 1.291 1.276 5* −13.541 0.750 1.544 56.4 7.736 3.6146* −3.273 0.679 7* −20.063 0.710 1.635 23.9 5.873 8* −3.188 0.056 9 Infinite 0.076 (diaphragm) 10  7.740 1.320 1.697 55.46 2.821 3.355 11 −2.450 0.271 12*  −4.136 0.500 1.635 23.9 −1.168 8.497 13*  0.946 2.1801.544 56.4 1.601 14*  −2.056 0.944 15  Infinite 0.400 16  Infinite 0.125

In Table 7 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 8-1 Surface c (1/radius of curvature) K A4 A6 3  4.33971E−020.00000E+00 −6.82448E−03   3.73911E−03 4  7.74346E−01 −5.39587E+00 2.32631E−01 −1.17492E−01 5 −7.38477E−02 0.00000E+00 2.29113E−02 4.37979E−03 6 −3.05528E−01 0.00000E+00 4.74057E−02 −5.28192E−03 7−4.98442E−02 0.00000E+00 4.27102E−02 −4.22032E−04 8 −3.13660E−010.00000E+00 3.38907E−02  3.26534E−03 12 −2.41789E−01 0.00000E+00−3.09436E−02   3.41185E−02 13  1.05668E+00 −1.00000E+00  5.66189E−04−1.14232E−02 14 −4.86390E−01 0.00000E+00 7.16605E−02 −6.17165E−02

TABLE 8-2 Surface A8 A10 A12 A14 A16 3 −1.15147E−03   1.50789E−04−7.30801E−06  0.00000E+00 0.00000E+00 4 7.01048E−02 −7.98133E−03−4.17335E−03  0.00000E+00 0.00000E+00 5 1.21716E−02 −8.91664E−030.00000E+00 0.00000E+00 0.00000E+00 6 2.05279E−02 −2.11693E−025.41203E−03 0.00000E+00 0.00000E+00 7 6.15517E−03  0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 8 8.49340E−03  3.83965E−03−2.61241E−03  0.00000E+00 0.00000E+00 12 −5.25642E−02   5.03801E−02−2.60337E−02  5.67639E−03 0.00000E+00 13 1.93193E−02 −2.02628E−021.27147E−02 −3.03203E−03  0.00000E+00 14 5.37377E−02 −2.41958E−025.72598E−03 −5.29799E−04  0.00000E+00

In Table 8-1 and Table 8-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 8-1 and Table 8-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.404 mm, and the entrance pupil diameter HEP is 0.498 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.404 mm, and the effective focal length f of the lens system as awhole is 1.011 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.011 mm, and the entrance pupildiameter HEP is 0.498 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 6.571 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.355 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.355 mm, and the effective focal length f of the lenssystem as a whole is 1.011 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 14A to FIG. 16L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 17 illustrates a wide-angle lens according to Embodiment 5 of thedisclosure. FIG. 18A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 5 of the disclosure. FIG.18B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 5 of the disclosure. FIG. 19A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 5 of the disclosure. FIG. 19Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 5 of the disclosure. FIG. 20A toFIG. 20L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 5 of the disclosure. Here, in FIG. 18A, FIG.18B, FIG. 19A, FIG. 19B, and FIG. 20A to FIG. 20L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 20A to FIG. 20L, the maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 17, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 17, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.021 mm, the object-to-image distance (total track) d is13.398 mm, the F value (image space F/#) is 2, the maximum HFOV (maximumhalf field angle) is 108 degrees, and the entrance pupil diameter HEP is0.511 mm.

Table 9 shows physical properties of each surface of the wide-angle lens1000 of this embodiment. Table 10-1 and Table 10-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 9 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  11.8501.800 1.871 40.73 −4.662 −1.258 4.142 2  2.810 1.790 3* 21.109 0.6101.544 56.4 −2.419 4* 1.226 1.511 5* −41.052 0.645 1.544 56.4 7.227 3.2596* −3.608 0.559 7* 35.384 0.625 1.635 23.9 5.224 8* −3.636 0.050 9 Infinite 0.157 (diaphragm) 10  6.330 1.200 1.697 55.46 3.312 3.679 11 −3.350 0.180 12*  −5.730 0.510 1.635 23.9 −1.201 9.670 13*  0.910 2.2501.544 56.4 1.592 14*  −2.306 0.986 15  Infinite 0.400 16  Infinite 0.125

In Table 9 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 10-1 Surface c (1/radius of curvature) K A4 A6 3  4.73738E−020.00000E+00 −5.16461E−03  2.97096E−03 4  8.15727E−01 −3.85594E+00 2.02517E−01 −7.83664E−02  5 −2.43593E−02 0.00000E+00 7.18080E−041.54312E−02 6 −2.77185E−01 0.00000E+00 1.27000E−02 1.84355E−02 7 2.82614E−02 0.00000E+00 1.29430E−02 2.83444E−02 8 −2.75058E−010.00000E+00 5.20665E−03 2.87756E−02 12 −1.74511E−01 0.00000E+00−2.22912E−02  −2.24026E−04  13  1.09890E+00 −1.00000E+00  5.45916E−02−8.55229E−02  14 −4.33708E−01 0.00000E+00 5.56964E−02 −4.87201E−02 

TABLE 10-2 Surface A8 A10 A12 A14 A16 3 −1.12779E−03   1.69605E−04−9.24708E−06  0.00000E+00 0.00000E+00 4 5.54759E−02 −1.43828E−02−3.40212E−05  0.00000E+00 0.00000E+00 5 4.27755E−03 −5.97392E−030.00000E+00 0.00000E+00 0.00000E+00 6 1.27283E−03 −1.01399E−022.46941E−03 0.00000E+00 0.00000E+00 7 −2.19533E−02   8.91100E−030.00000E+00 0.00000E+00 0.00000E+00 8 −2.59952E−02   1.31396E−020.00000E+00 0.00000E+00 0.00000E+00 12 −5.53989E−03   2.10400E−02−2.03506E−02  6.17103E−03 0.00000E+00 13 7.91865E−02 −3.44941E−023.84031E−03 7.90842E−04 0.00000E+00 14 4.18221E−02 −1.79457E−023.88481E−03 −3.05248E−04  0.00000E+00

In Table 10-1 and Table 10-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 10-1 and Table 10-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.398 mm, and the entrance pupil diameter HEP is 0.511 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.398 mm, and the effective focal length f of the lens system as awhole is 1.021 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.021 mm, and the entrance pupildiameter HEP is 0.511 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 4.142 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.679 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.679 mm, and the effective focal length f of the lenssystem as a whole is 1.021 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 18A to FIG. 20L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 21 illustrates a wide-angle lens according to Embodiment 6 of thedisclosure. FIG. 22A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 6 of the disclosure. FIG.22B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 6 of the disclosure. FIG. 23A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 6 of the disclosure. FIG. 23Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 6 of the disclosure. FIG. 24A toFIG. 24L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 6 of the disclosure. Here, in FIG. 22A, FIG.22B, FIG. 23A, FIG. 23B, and FIG. 24A to FIG. 24L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 24A to FIG. 24L, the maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 21, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 21, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.018 mm, the object-to-image distance (total track) d is13.383 mm, the F value (image space F/#) is 2, the maximum HFOV (maximumhalf field angle) is 108 degrees, and the entrance pupil diameter HEP is0.509 mm.

Table 11 shows physical properties of each surface of the wide-anglelens 1000 of this embodiment. Table 12-1 and Table 12-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 11 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  12.5001.700 1.871 40.73 −4.748 −1.310 4.528 2  2.910 1.880 1.000 3* 9.1490.600 1.544 56.4 −2.585 4* 1.191 1.354 1.000 5* −14.140 0.750 1.544 56.49.374 3.338 6* −3.818 0.381 1.000 7* −22.250 0.722 1.635 23.9 4.796 8*−2.713 0.050 1.000 9  Infinite 0.130 1.000 (diaphragm) 10  7.740 1.3201.697 55.46 2.821 3.546 11  −2.450 0.199 1.000 12*  −3.600 0.510 1.63523.9 −1.147 10.463 13*  0.963 2.282 1.544 56.4 1.648 14*  −2.141 0.9801.000 15  Infinite 0.400 16  Infinite 0.125

In Table 11 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 12-1 Surface c (1/radius of curvature) K A4 A6 3  1.09306E−010.00000E+00 −4.51092E−03  2.92728E−03 4  8.39842E−01 −3.71100E+00 2.15910E−01 −7.58275E−02  5 −7.07214E−02 0.00000E+00 −5.47555E−03 1.09203E−02 6 −2.61938E−01 0.00000E+00 1.43606E−02 2.26240E−02 7−4.49438E−02 0.00000E+00 1.40010E−02 4.01310E−02 8 −3.68664E−010.00000E+00 1.66786E−02 2.21644E−02 12 −2.77778E−01 0.00000E+00−2.23667E−02  7.48072E−03 13  1.03842E+00 −1.00000E+00  4.72309E−02−6.05266E−02  14 −4.67071E−01 0.00000E+00 5.78738E−02 −4.73130E−02 

TABLE 12-2 Surface A8 A10 A12 A14 A16 3 −1.14938E−03  1.63223E−04−7.82147E−06  0.00000E+00 0.00000E+00 4  5.61909E−02 −1.28652E−02−3.10366E−04  0.00000E+00 0.00000E+00 5  2.71037E−03 −6.63668E−030.00000E+00 0.00000E+00 0.00000E+00 6 −3.16016E−03 −9.85165E−032.97746E−03 0.00000E+00 0.00000E+00 7 −1.96461E−02  8.38631E−030.00000E+00 0.00000E+00 0.00000E+00 8 −1.03312E−02  1.03923E−020.00000E+00 0.00000E+00 0.00000E+00 12 −8.59213E−03  1.81642E−02−1.67818E−02  5.17215E−03 0.00000E+00 13  5.15225E−02 −2.02257E−021.88707E−03 3.30690E−04 0.00000E+00 14  4.12895E−02 −1.76625E−023.69776E−03 −2.59955E−04  0.00000E+00

In Table 12-1 and Table 12-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 12-1 and Table 12-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.383 mm, and the entrance pupil diameter HEP is 0.509 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.383 mm, and the effective focal length f of the lens system as awhole is 1.018 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.018 mm, and the entrance pupildiameter HEP is 0.509 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 4.528 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.546 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.546 mm, and the effective focal length f of the lenssystem as a whole is 1.018 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 22A to FIG. 24L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 25 illustrates a wide-angle lens according to Embodiment 7 of thedisclosure. FIG. 26A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 7 of the disclosure. FIG.26B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 7 of the disclosure. FIG. 27A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 7 of the disclosure. FIG. 27Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 7 of the disclosure. FIG. 28A toFIG. 28L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 7 of the disclosure. Here, in FIG. 26A, FIG.26B, FIG. 27A, FIG. 27B, and FIG. 28A to FIG. 28L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 28A to FIG. 28L, a maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 25, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110 (located closestto the object side), the second lens 120 (located on the image side ofand adjacent to the first lens 110), the third lens 130, the fourth lens140, the fifth lens 150, the sixth lens 160 and the seventh lens 170 haspositive refractive power or negative refractive power, whether each ofthese lenses is a glass lens or plastic lens, whether the object sidesurface and the image side surface of each of these lenses are convexsurfaces or concave surfaces, and whether the object side surface andthe image side surface are spherical surfaces or aspheric surfaces) asthat of the wide-angle lens of Embodiment 1, and thus the detailsthereof will be omitted.

In addition, as shown in FIG. 25, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.019 mm, the object-to-image distance (total track) d is13.381 mm, the F value (image space F/#) is 2.0163, the maximum HFOV(maximum half field angle) is 108 degrees, and the entrance pupildiameter HEP is 0.505 mm.

Table 13 shows physical properties of each surface of the wide-anglelens 1000 of this embodiment. Table 14-1 and Table 14-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 13 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  12.5001.700 1.871 40.73 −4.748 −1.310 4.815 2  2.910 1.880 3* 9.138 0.6001.544 56.4 −2.586 4* 1.191 1.354 5* −11.789 0.750 1.544 56.4 10.0473.394 6* −3.818 0.381 7* −22.250 0.710 1.635 23.9 4.797 8* −2.713 0.0509  Infinite 0.116 (diaphragm) 10  7.740 1.320 1.697 55.46 2.821 3.55711  −2.450 0.225 12*  −3.600 0.510 1.635 23.9 −1.147 10.463 13*  0.9632.282 1.544 56.4 1.648 14*  −2.141 0.978 15  Infinite 0.400 16  Infinite0.125

In Table 11 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 14-1 Surface c (1/radius of curvature) K A4 A6 3  1.09439E−010.00000E+00 −4.39546E−03  2.94241E−03 4  8.39842E−01 −3.71100E+00 2.15910E−01 −7.58275E−02  5 −8.48248E−02 0.00000E+00 −5.99821E−03 9.40179E−03 6 −2.61938E−01 0.00000E+00 1.43606E−02 2.26240E−02 7−4.49438E−02 0.00000E+00 1.40010E−02 4.01310E−02 8 −3.68664E−010.00000E+00 1.66786E−02 2.21644E−02 12 −2.77778E−01 0.00000E+00−2.23667E−02  7.48072E−03 13  1.03842E+00 −1.00000E+00  4.72309E−02−6.05266E−02  14 −4.67071E−01 0.00000E+00 5.76337E−02 −4.72421E−02 

TABLE 14-2 Surface A8 A10 A12 A14 A16 3 −1.15296E−03  1.63212E−04−7.75247E−06  0.00000E+00 0.00000E+00 4  5.61909E−02 −1.28652E−02−3.10366E−04  0.00000E+00 0.00000E+00 5  3.12004E−03 −6.74245E−030.00000E+00 0.00000E+00 0.00000E+00 6 −3.16016E−03 −9.85165E−032.97746E−03 0.00000E+00 0.00000E+00 7 −1.96461E−02  8.38631E−030.00000E+00 0.00000E+00 0.00000E+00 8 −1.03312E−02  1.03923E−020.00000E+00 0.00000E+00 0.00000E+00 12 −8.59213E−03  1.81642E−02−1.67818E−02  5.17215E−03 0.00000E+00 13  5.15225E−02 −2.02257E−021.88707E−03 3.30690E−04 0.00000E+00 14  4.13120E−02 −1.76585E−023.69817E−03 −2.61279E−04  0.00000E+00

In Table 14-1 and Table 14-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 14-1 and Table 14-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.381 mm, and the entrance pupil diameter HEP is 0.505 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.381 mm, and the effective focal length f of the lens system as awhole is 1.019 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.019 mm, and the entrance pupildiameter HEP is 0.505 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 4.815 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.557 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.557 mm, and the effective focal length f of the lenssystem as a whole is 1.019 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 26A to FIG. 28L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 29 illustrates a wide-angle lens according to Embodiment 8 of thedisclosure. FIG. 30A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 8 of the disclosure. FIG.30B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 8 of the disclosure. FIG. 31A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 8 of the disclosure. FIG. 31Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 8 of the disclosure. FIG. 32A toFIG. 32L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 8 of the disclosure. Here, in FIG. 30A, FIG.30B, FIG. 31A, FIG. 31B, and FIG. 32A to FIG. 32L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 32A to FIG. 32L, the maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 29, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 29, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.030 mm, the object-to-image distance (total track) d is13.609 mm, the F value (image space F/#) is 2, the maximum HFOV (maximumhalf field angle) is 106 degrees, and the entrance pupil diameter HEP is0.515 mm.

Table 15 shows physical properties of each surface of the wide-anglelens 1000 of this embodiment. Table 16-1 and Table 16-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 15 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  12.6411.659 1.804 46.5 −5.702 −1.262 21.864 2  3.168 1.968 3* −22.811 0.6001.544 56.4 −2.189 4* 1.268 1.587 5* 3.542 1.200 1.544 56.4 10.255 3.6236* 8.543 0.036 7* 4.456 0.592 1.639 23.5 4.851 8* −9.668 0.248 9 Infinite 0.078 (diaphragm) 10  6.001 1.129 1.697 55.46 2.908 3.125 11 −2.824 0.247 12*  −5.445 0.500 1.639 23.5 −1.380 6.310 13*  1.090 2.1701.544 56.4 1.720 14*  −1.971 1.070 15  Infinite 0.400 16  Infinite 0.125

In Table 15 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 16-1 Surface c (1/radius of curvature) K A4 A6 3 −4.38390E−02 0.00000E+00 1.02948E−02 −1.01140E−03  4 7.88668E−01 −1.13571E+00 5.66499E−02 1.84231E−03 5 2.82343E−01 0.00000E+00 −2.18543E−02 5.16357E−03 6 1.17050E−01 0.00000E+00 −6.48711E−02  −8.41810E−03  72.24418E−01 0.00000E+00 3.04785E−02 1.99197E−02 8 −1.03429E−01 0.00000E+00 9.05286E−02 3.48783E−02 12 −1.83670E−01  0.00000E+00−3.32106E−02  4.95833E−02 13 9.17180E−01 −3.67711E+00  1.58393E−01−3.03404E−02  14 −5.07238E−01  −6.42125E−01  3.25791E−02 −8.99922E−03 

TABLE 16-2 Surface A8 A10 A12 A14 A16 3 2.82136E−05 8.57444E−160.00000E+00 0.00000E+00 0.00000E+00 4 3.99185E−02 −2.56858E−02 9.68214E−03 0.00000E+00 0.00000E+00 5 −3.88312E−04  0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 6 3.26148E−03 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 7 −6.50576E−03  0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 8 4.33217E−03 0.00000E+000.00000E+00 0.00000E+00 0.00000E+00 12 −4.63097E−02  2.53604E−02−5.68334E−03  0.00000E+00 0.00000E+00 13 −2.77646E−02  2.45247E−02−5.43979E−03  0.00000E+00 0.00000E+00 14 4.06471E−03 −7.04269E−04 4.21913E−05 0.00000E+00 0.00000E+00

In Table 16-1 and Table 16-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 16-1 and Table 16-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.609 mm, and the entrance pupil diameter HEP is 0.515 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.609 mm, and the effective focal length f of the lens system as awhole is 1.030 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.030 mm, and the entrance pupildiameter HEP is 0.515 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 21.864 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.125 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.125 mm, and the effective focal length f of the lenssystem as a whole is 1.030 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 30A to FIG. 32L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

FIG. 33 illustrates a wide-angle lens according to Embodiment 9 of thedisclosure. FIG. 34A illustrates curvature of field and distortion ofthe wide-angle lens according to Embodiment 9 of the disclosure. FIG.34B illustrates curvature of field and distortion of the wide-angle lensaccording to Embodiment 9 of the disclosure. FIG. 35A illustrateslateral chromatic aberration (transverse chromatic aberration) of thewide-angle lens according to Embodiment 9 of the disclosure. FIG. 35Billustrates spherical aberration (longitudinal aberration) of thewide-angle lens according to Embodiment 9 of the disclosure. FIG. 36A toFIG. 36L illustrate transverse aberration of the wide-angle lensaccording to Embodiment 9 of the disclosure. Here, in FIG. 34A, FIG.34B, FIG. 35A, FIG. 35B, and FIG. 36A to FIG. 36L, a correlation curveof red light R (having a wavelength of 656 nm) is denoted by R, acorrelation curve of green light G (having a wavelength of 588 nm) isdenoted by G, and a correlation curve of blue light B (having awavelength of 486 nm) is denoted by B. T indicates being related to themeridian plane, and S indicates being related to the sagittal plane.Moreover, in FIG. 36A to FIG. 36L, a maximum scale of the longitudinalaxis is ±50.000 μm.

As shown in FIG. 33, the wide-angle lens 1000 includes, sequentiallyarranged from the object side (L1 side), the first lens 110, the secondlens 120, the third lens 130, the fourth lens 140, the diaphragm 180,the fifth lens 150, the sixth lens 160 and the seventh lens 170. Amongthem, the sixth lens 160 and the seventh lens 170 are bonded together byan adhesive to constitute a cemented lens.

Here, the wide-angle lens 1000 in this embodiment has the same basicstructure (that is, whether each of the first lens 110, the second lens120, the third lens 130, the fourth lens 140, the fifth lens 150, thesixth lens 160 and the seventh lens 170 has positive refractive power ornegative refractive power, whether each of these lenses is a glass lensor plastic lens, whether the object side surface and the image sidesurface of each of these lenses are convex surfaces or concave surfaces,and whether the object side surface and the image side surface arespherical surfaces or aspheric surfaces) as that of the wide-angle lensof Embodiment 1, and thus the details thereof will be omitted.

In addition, as shown in FIG. 33, similarly to Embodiment 1, thelight-shielding sheet 190 is provided between the second lens 120 andthe third lens 130, the filter 200 is arranged on the image side of theseventh lens 170, and the imaging element 300 is arranged on the imageside of the filter 200.

In this embodiment, in the lens system as a whole, the effective focallength f is 1.019 mm, the object-to-image distance (total track) d is13.397 mm, the F value (image space F/#) is 2.012, the maximum HFOV(maximum half field angle) is 108.004 degrees, and the entrance pupildiameter HEP is 0.506 mm.

Table 17 shows physical properties of each surface of the wide-anglelens 1000 of this embodiment. Table 18-1 and Table 18-2 show asphericcoefficients of each surface of the wide-angle lens 1000 of thisembodiment.

TABLE 17 Effective Effective Effective Radius of focal focal focalSurface curvature Thickness N_(d) v_(d) length length length 1  12.1001.730 1.871 40.73 −4.823 −1.415 26.363 2  2.910 1.765 3* 7.693 0.6001.544 56.4 −2.800 4* 1.237 1.517 5* −6.607 0.850 1.544 56.4 12.527 4.3816* −3.507 0.202 7* −12.641 0.700 1.635 23.9 6.634 8* −3.228 0.050 9 Infinite 0.129 (diaphragm) 10  5.000 1.360 1.697 55.46 2.636 3.374 11 −2.580 0.260 12*  −3.864 0.550 1.635 23.9 −1.179 10.147 13*  0.980 2.1901.544 56.4 1.642 14*  −2.151 0.969 15  Infinite 0.400 16  Infinite 0.125

In Table 17 above, the radius of curvature, thickness, and effectivefocal length are in units of mm. N_(d) represents a refractive index fora ray of 587.56 nm. v_(d) represents the Abbe number. * represents anaspheric surface.

TABLE 18-1 Surface c (1/radius of curvature) K A4 A6 3  1.29990E−010.00000E+00 1.79733E−03 −1.14149E−03 4  8.08669E−01 −4.00000E+00 2.15100E−01 −8.02378E−02 5 −1.51355E−01 0.00000E+00 −1.09624E−02 −8.73052E−03 6 −2.85185E−01 0.00000E+00 4.64269E−03  4.90763E−03 7−7.91052E−02 0.00000E+00 1.02155E−02  7.50888E−03 8 −3.09828E−010.00000E+00 7.49234E−03  1.54584E−03 12 −2.58792E−01 0.00000E+00−3.14257E−02   2.35226E−03 13  1.02041E+00 −1.00000E+00  3.07479E−02−4.89661E−02 14 −4.64857E−01 0.00000E+00 4.79842E−02 −2.97957E−02

TABLE 18-2 Surface A8 A10 A12 A14 A16 3 −6.11588E−05   1.50045E−053.90615E−08 0.00000E+00 0.00000E+00 4 4.96308E−02 −1.37651E−021.87863E−04 0.00000E+00 0.00000E+00 5 2.50539E−03 −1.94316E−04−2.18386E−04  0.00000E+00 0.00000E+00 6 2.37631E−03  4.68175E−041.19525E−03 0.00000E+00 0.00000E+00 7 1.14133E−02  6.53638E−040.00000E+00 0.00000E+00 0.00000E+00 8 1.36753E−02 −1.98505E−030.00000E+00 0.00000E+00 0.00000E+00 12 3.38366E−03 −2.00010E−036.86525E−04 0.00000E+00 0.00000E+00 13 2.79270E−02 −5.22149E−03−1.20343E−04  0.00000E+00 0.00000E+00 14 2.26165E−02 −7.19858E−039.87041E−04 0.00000E+00 0.00000E+00

In Table 18-1 and Table 18-2 above, in a case where a lens surface is aconvex surface protruding toward the object side or a concave surfacerecessed toward the object side, its radius of curvature is set to apositive value; in a case where a lens surface is a convex surfaceprotruding toward the image side or a concave surface recessed towardthe image side, its radius of curvature is set to a negative value.

In addition, Table 18-1 and Table 18-2 above show the asphericcoefficients A4, A6, A8, A10, A12, A14 and A16 of each of the asphericsurfaces, which satisfy Expression 1 above.

Here, in the wide-angle lens 1000, the object-to-image distance d is13.397 mm, and the entrance pupil diameter HEP is 0.506 mm. Therefore,the following condition 1 is satisfied:

d/HEP<29.000  (1)

In condition 1, if d/HEP is 29.000 or greater, it is difficult to ensurethe optical performance while preventing the overall length of the lenssystem from becoming excessively large.

In contrast, in this embodiment, since condition 1 is satisfied, it iseasy to ensure the optical performance while preventing the overalllength of the lens system from becoming excessively large.

Particularly, in this embodiment, since d/HEP<27.000 is satisfied, it isrelatively easy to ensure the optical performance while preventing theoverall length of the lens system from becoming excessively large.

In addition, in the wide-angle lens 1000, the object-to-image distance dis 13.397 mm, and the effective focal length f of the lens system as awhole is 1.019 mm. Therefore, the following condition 2 is satisfied:

11.000<d/f<15.000  (2)

In condition 2, if d/f is 11.000 or less, it is difficult toappropriately correct various aberrations. On the other hand, if d/f is15.000 or greater, the overall length of the lens system becomesexcessively large.

In contrast, in this embodiment, since condition 2 is satisfied, it iseasy to appropriately correct various aberrations, making it easy toachieve good optical characteristics. Moreover, it is possible toprevent the lens system from becoming excessively large while avoidingan excessively large overall length of the lens system.

In addition, in the wide-angle lens 1000, the effective focal length fof the lens system as a whole is 1.019 mm, and the entrance pupildiameter HEP is 0.506 mm. Therefore, the following condition 3 issatisfied:

f/HEP<2.3  (3)

In condition 3, if f/HEP is 2.3 or greater, it is difficult to ensurethe brightness.

In contrast, in this embodiment, since condition 3 is satisfied, it ispossible to ensure the brightness and to enable application in ahigh-density imaging element.

In addition, in the wide-angle lens 1000, the combined effective focallength f1234 of the first lens 110, the second lens 120, the third lens130, and the fourth lens 140 is 26.363 mm, and the combined effectivefocal length f567 of the fifth lens 150, the sixth lens 160, and theseventh lens 170 is 3.374 mm. Therefore, the following condition 4 issatisfied:

0.800<f1234/f4567<8.000  (4)

In condition 4, if f1234/f567 is 0.800 or less, the refractive power ofthe front lens group composed of the first lens, the second lens, thethird lens, and the fourth lens is excessively high, making it difficultto appropriately correct various aberrations. On the other hand, iff1234/f567 is 8.000 or greater, the refractive power of the front lensgroup composed of the first lens, the second lens, the third lens, andthe fourth lens is excessively low, making it difficult to reduce thediameter of each lens of the front lens group and to miniaturize thewide-angle lens as a whole.

In contrast, in this embodiment, since condition 4 is satisfied, it iseasy to appropriately correct various aberrations and to realizeminiaturization.

In addition, in the wide-angle lens 1000, the combined effective focallength f567 of the fifth lens 150, the sixth lens 160, and the seventhlens 170 is 3.374 mm, and the effective focal length f of the lenssystem as a whole is 1.019 mm. Therefore, the following condition 5 issatisfied:

2.800<f567/f<3.850  (5)

In condition 5, if f567/f is 2.800 or less, the refractive power of therear lens group composed of the fifth lens, the sixth lens, and theseventh lens is excessively high, making it difficult to appropriatelycorrect various aberrations, especially chromatic aberration. On theother hand, if f567/f is 3.850 or greater, it is difficult to reduce thediameter of each lens and the object-to-image distance, thus making itdifficult to miniaturize the wide-angle lens as a whole.

In contrast, in this embodiment, since condition 5 is satisfied, it iseasy to appropriately correct various aberrations, especially chromaticaberration, and to realize miniaturization.

In summary, in this embodiment, by configuring the wide-angle lens 1000as above, as shown in FIG. 34A to FIG. 36L, it is easy to ensure theoptical performance while preventing the overall length of the lenssystem from becoming excessively large.

The disclosure has been exemplarily described above with reference tothe accompanying drawings, and it is obvious that the specificimplementation of the disclosure is not limited by the foregoingembodiments.

For example, in the foregoing embodiments, the form of the first surface1 of the first lens 110, the form of the third surface 3 of the secondlens 120, the form of the fifth surface 5 of the third lens 130, theform of the seventh surface 7 of the fourth lens 140, and the form ofthe twelfth surface 12 of the sixth lens 160 may be appropriatelychanged as needed.

In addition, in the foregoing embodiments, the first lens 110 and thefifth lens 150 may be composed of plastic lenses, and the second lens120, the third lens 130, the fourth lens 140, the sixth lens 160 and theseventh lens 170 may be composed of glass lenses.

Features of the above-described preferred embodiments and themodifications thereof may be combined appropriately as long as noconflict arises.

While preferred embodiments of the present disclosure have beendescribed above, it is to be understood that variations andmodifications will be apparent to those skilled in the art withoutdeparting from the scope and spirit of the present disclosure. The scopeof the present disclosure, therefore, is to be determined solely by thefollowing claims.

What is claimed is:
 1. A wide-angle lens, comprising: a first lens, asecond lens, a third lens, a fourth lens, a diaphragm, a fifth lens, asixth lens, and a seventh lens, sequentially arranged from an objectside, wherein an object-to-image distance of the wide-angle lens is setto d, an entrance pupil diameter of the wide-angle lens is set to HEP,and d/HEP<29.000 is satisfied.
 2. The wide-angle lens according to claim1, wherein d/HEP<27.000 is satisfied.
 3. The wide-angle lens accordingto claim 1, wherein an effective focal length of the wide-angle lens asa whole is set to f, and 11.000<d/f<15.000 is satisfied.
 4. Thewide-angle lens according to claim 1, wherein an effective focal lengthof the wide-angle lens as a whole is set to f, and f/HEP<2.3 issatisfied.
 5. The wide-angle lens according to claim 2, wherein aneffective focal length of the wide-angle lens as a whole is set to f,and f/HEP<2.3 is satisfied.
 6. The wide-angle lens according to claim 3,wherein an effective focal length of the wide-angle lens as a whole isset to f, and f/HEP<2.3 is satisfied.
 7. The wide-angle lens accordingto claim 1, wherein the sixth lens and the seventh lens constitute acemented lens, the first lens is a negative lens with a concave surfacefacing an image side, the second lens is a negative lens with a concavesurface facing the image side, the third lens is a positive lens with aconvex surface facing the image side, the fourth lens is a positive lenswith a convex surface facing the image side, the fifth lens is apositive lens with a convex surface facing the object side and a convexsurface facing the image side, the sixth lens is a negative lens with aconcave surface facing the image side, the seventh lens is a positivelens with a convex surface facing the object side and a convex surfacefacing the image side, and a combined effective focal length of thefirst lens, the second lens, the third lens, and the fourth lens is setto f1234, a combined effective focal length of the fifth lens, the sixthlens, and the seventh lens is set to f567, and 0.800<f1234/f4567<8.000is satisfied.
 8. The wide-angle lens according to claim 1, wherein thesixth lens and the seventh lens constitute a cemented lens, the firstlens is a negative lens with a concave surface facing an image side, thesecond lens is a negative lens with a concave surface facing the imageside, the third lens is a positive lens with a convex surface facing theimage side, the fourth lens is a positive lens with a convex surfacefacing the image side, the fifth lens is a positive lens with a convexsurface facing the object side and a convex surface facing the imageside, the sixth lens is a negative lens with a concave surface facingthe image side, the seventh lens is a positive lens with a convexsurface facing the object side and a convex surface facing the imageside, and a combined effective focal length of the fifth lens, the sixthlens, and the seventh lens is set to f567, an effective focal length ofthe wide-angle lens as a whole is set to f, and 2.800<f567/f<3.850 issatisfied.
 9. The wide-angle lens according to claim 1, wherein thefirst lens and the fifth lens are each a glass lens, and the secondlens, the third lens, the fourth lens, the sixth lens, and the seventhlens are each a plastic lens.